The general goal of this proposed investigation is to develop expedient regio- and stereochemically controlled synthetic methods for the two most significant mycotoxins: trichothecenes and aflatoxins. Furthermore, through these studies we hope to obtain pertinent information on the mechanisms of some fundamental synthetic organic reactions such as the inter- and intramolecular Diels-Alder reactions and heteroatom-directed metalation reactions. We wish to propose synthetic studies in the area of mycotoxins with the following specific aims: 1) to develop a few efficient and regio- and stereochemically controlled synthetic methods amenable to the synthesis of the various functionalized trichothecene skeltons, 2) to synthesize the macrocyclic chain of baccharin, and thus, complete the total synthesis of this antileukemic agent, 3) to develop a novel synthetic route to aflatoxins using heteroatom-directed metalation reactions, and 4) to synthesize putative biosynthetic intermediates to aflatoxin B1, averufin and nidurufin in optically active forms and determine their absolute configurations.